datomic.clj

;; Schema
     {:db/id #db/id[:db.part/db]
      :db/ident :thing/name
      :db/valueType :db.type/string
      :db/cardinality :db.cardinality/one
      :db/fulltext true
      :db/doc "A thing's name"
      :db.install/_attribute :db.part/db}

     {:db/id #db/id[:db.part/db]
      :db/ident :thing/children
      :db/valueType :db.type/ref
      :db/cardinality :db.cardinality/many
      :db/doc "A thing's child things"
      :db.install/_attribute :db.part/db}

;; Query (does not work)
;; Trying to find out what parents Pokahontas has
(q '[:find ?name
     :where [?e :thing/name "Pokahontas"]
            [?e :thing/_children ?p]
            [?p :thing/name ?name]]
   (db conn))

;; This works. But feels super clunky.
(def pokahontas
  (d/entity (db conn)
            (-> (q '[:find ?e
                     :where [?e :thing/name "Pokahontas"]]
                   (db conn))
              first first)))

(map #(get % :thing/name) (get pokahontas :thing/_children))



;; For future visitors I figured it out. This works:



(q '[:find ?name
     :where [?e :thing/name "Pokahontas"]
            [?p :thing/children ?e]
            [?p :thing/name ?name]]
   (db conn))